Field devices, such as those marketed by Endress+Hauser, need a power supply for their operation. Such a power supply, e.g., in the form of a supply voltage, can nowadays be provided for the field devices in different ways. Thus, it has become known from the German patent application, DE 102011076708 A1 to supply a field device with electrical energy via a power supply unit. In addition to that, there is a possibility of supplying a field device with electrical energy from a fuel cell or a solar panel. It has also become known that field devices can be supplied with power via a so-called two-wire current loop.
Field devices thereby represent all process-oriented devices—i.e., those used in an industrial plant—such as, for example, display units, sensors, actuators, data loggers, or radio units.
However, one disadvantage of the known field devices lies in the fact that they are all designed for only one form of power supply mentioned above.